1. Field
Embodiments of the present invention relate to a pre-fill system to improve brake feel and a method of increasing an initial flux using the same which may reduce an invalid travel distance of a brake pedal.
2. Description of the Related Art
In general, a hydraulic brake system of a vehicle generates hydraulic brake pressure by pressing the oil supplied to a master cylinder from a reservoir and transfers the generated brake pressure to each wheel through a hydraulic pressure line of a brake. Braking operation is performed as the hydraulic brake pressure transferred to each wheel is again delivered to the corresponding disc brake, which generates a brake torque by applying pressure to both sides of a disc that rotates together with the wheel.
FIG. 1 is a view schematically illustrating a conventional hydraulic brake apparatus. With reference to FIG. 1, the hydraulic brake apparatus includes a booster 20 to amplify effort force on a brake pedal 10, a master cylinder 30 to convert force generated by the booster 20 into a hydraulic pressure, and a reservoir 40 coupled to an upper portion of the master cylinder 30 to supply oil to the master cylinder 30. The hydraulic brake apparatus generates braking force by transferring hydraulic brake pressure to a disc brake 60 installed at each wheel 1 through a hydraulic line 50 according to a driver's effort force.
However, when such hydraulic brake apparatus is used to perform braking, braking is not effected at the moment force is applied to the brake pedal 10, but is initiated after the brake pedal 10 travels a certain distance forward. The distance that the brake pedal 10 travels from the moment the brake pedal 10 begins to be depressed to when braking is initiated is referred to as a lost travel section (hereinafter, LT section). Brake feel improves with decreasing length of the LT section. If the LT section is extended, it may cause the driver to feel that the brake does not work and be dissatisfied with braking when he applies pressure to the brake pedal 10, and it may even an accident.
The length of this LT section is affected by the distance from the brake pedal 10 to the master cylinder 30 and the booster 20, the time at which pressure begins to rise in the master cylinder 30, the distance between the pads of the disc brake 60 and the disc, and the like. When the vehicle travels on an unpaved road such as an uneven road, the distance between the pads of the disc brake 60 and the disc increases, extending the LT section and resulting in degradation of pedal feel.